Fluorescent tubes

[pumpkin]

This may be a dumb question, so here goes.We have in one garage 18 lights that were installed 10 years ago and never repaced one yet. They all are working but they seem to be not as bright as first installed. Is it my eyes or can fluorescent lights loose their brightness and still work.

[Dreamcast18]

1. Temperature plays a key part in brightness:
http://en.wikipedia.org/wiki/Fluorescent_lamp#Usage

2. As with all things, the lamp/brightness will decay over time. So the
bulb will keep burning while it goes below 70-90% brightness.


This may be a dumb question, so here goes.We have in one garage 18 lights that were installed 10 years ago and never repaced one yet. They all are working but they seem to be not as bright as first installed. Is it my eyes or can fluorescent lights loose their brightness and still work.

Thanks in advance.

[pumpkin]

Thanks a lot.